Production of 2,2-disubstituted propiolactones

ABSTRACT

WHEREIN R is an alkyl group of from 1 to 4 carbon atoms and R1 is an alkyl group of from 1 to 4 carbon atoms or a phenyl group. The process is operable at temperatures from about 240*C. to about 360*C. with contact times ranging from about 0.1 second to about 30.0 seconds. The gaseous ester feed may, if desired, be diluted with an inert gas such as nitrogen and the reactor may be run at atmospheric pressure or reduced pressure. Both acidic and basic catalysts have been found effective in this pyrolysis. The present invention relates to a process for the manufacture of 2,2-disubstituted propiolactones via the pyrolysis of methylene diisoalkylate in the vapor phase over a fixed bed catalyst system. The reaction of the invention is as follows:

States Patent Allen et al.

[ PRODUCTION OF 2,2-DISUBST1TUTED Primary Examiner-Donald G. Daus PRUPKOLACTONES Assistant Examiner-Anne Marie T. Tighe Inventors: Robert P. Allen; g j. gttganrneyilfgent, 0r FlrmEdward R. Weber; Cecil D.

l-lagemeyer, .lr., both of Longview, u T ex 57 ABSTRACT [73] Asslgnee: g z Company The present invention relates to a process for the man- OC es ufacture of 2,2-disubstituted propiolactones via the [22] Filed: Nov. 3, i972 pyrolysis of methylene diisoalkylate in the vapor phase over a fixed bed catalyst system. The reaction of the [21] Appl' 303570 invention is as follows:

H R R O -O O- i fi R 5 3-0-11 R 61 i w ml R H [52] US. Cl. 260/3439 wherein R is an alkyl group of from 1 to 4 carbon [51] llnt. Cl atoms and R is an alkyl group of from 1 to 4 carbon [58] Field of Search 260/3439 atoms or a phenyl group. The process is operable at temperatures from about 240C. to about 360C. with [56] References Cited contact times ranging from about 0.1 second to about UNlTED S S P N S 30.0 seconds. The gaseous ester feed may, if desired, 3.436.406 4/1969 Nakahara et al. 260/3439 be d'luted an gas such mtroge and the reactor may be run at atmospheric pressure or re- FOREIGN PATENTS OR APPLICATIONS duced pressure. Both acidic and basic catalysts have 1,965,001 7/1971 Germany 260/3439 been found effective in this pyrolysis 22 Claims, No Drawings 11 2 PRUDTJCTION F ZQ-DHSUBSTHTUTET) 9 O 1L| Ba Se 9 PROPHUILACT NE L R R O S j; li 1carg% ??;}f 1 The present invention relates to a process for prepar- H R H R ing 2,2-disubstituted propiolactones by the pyrolysis of 5 a methylene diisoalkylate in the vapor phase over a fixed bed catalyst. R R 9 Q R R 2,2-disubstituted propiolactones are useful in the M J HIQOH polymer industry as starting material for synthetic res- R- il-H Pei- 144 Et ins and synthetic fibers. They are also useful in the 10 R tl 1 pharmaceutical industry and have heretofore been prepared by a variety of methods. For example, in US. Pat. NO. 2,356,459 there is described a well-known Base Catalyzed Rearrangement method for preparing 2,2-disubstituted propiolactones by the addition reaction of dimethyl ketene and formaldehyde. The known methods for the manufacture of H R Acid 2,2-disubstituted propiolactones, however, can be fi fi Z Caiali practiced on a commercial scale only with difficulties H and result in economic disadvantages.

lt is therefore an object of our invention to provide H a simplified method for the preparation of 2,2- R 9 H R (9 K R R R disubstituted propiolactones. x w kfl/ fi 1 it is another ob'ect to rovide a n -ste method for R H R R l J P 0 e P the preparation of 2,2disubstituted propiolactones. H

Other objects of the invention will become apparent from a consideration of the specification and claims of this application Acid Catalyzed Rearrangement The reaction of this invention is believed to proceed As discussed hereinabove, in the process of the inaccording to the following formula stant invention a gem diester having the formula H R R O R\ 0fi at L1i t-g R R 14 1'4 H R A H-ear -Oat H R H wherein R is an alkyl group of from 1-4 carbon atoms R O H O R 1 ll 1 and R 15 an alkyl group of 1-4 carbon atoms or a phel1-|-/-00-O ]9OO@ H1 nyl group. The reaction is operable at temperatures of R H R from about 240C. to about 360C. at contact times ranging from about 0.1 second to about 30 seconds. 40 Both acidic and basic catalysts have been found to be effective. is pyrolyzed in the vapor phase over a solid catalyst at There is no known prior art which discloses or prea temperature of from about 240C. to about 360C dicts this reaction process. Known methods to produce with a contact time of from about 0.1 second to about 'lola ton b transesterification re uire the res- 30 seconds. The aseous ester feed ma if desired be P C 6 Y q P g y 1 ence of the neopentyl structure to effect ring closure as diluted with an inert gas to facilitate feeding of the reillustrated below: actants, control of contact time, etc. Good results are 0 9H5 He H5 Ha O Hz-+ OH Helio-gH2 oH5 Ha OOH Ha H5 (-14% 0 l l H- -O No chemical mechanism is known which would suggest obtained at atmospheric pressure using an inert diluent that a neo structure could be formed from the methgas, usually in a molar ratio of gas to organic feed of ylene diisoalkylate starting material and subsequently from about 1:10 to about 20:], preferably about 1:1 to rearranged to form 2,2-disubstituted propiolactone. 6:1, and most preferably about 3:1 to 4:1. A suitable Likewise, no literature is known which would suggest 6O inert diluent gas is any gas which does not react with any m th d in hi h e hy ene s s COuld be cyeither the reactants or the products under the condiclized to form B-lactones It was, therefore, quite unex- {ions f h re tion, such as N argon, helium, gaseous PCCtGd that 2,2dlSUbStltUtd propiolactones could b8 hydrocarbons and compounds are rgadily vapor- Produced from methylene dlesters in a p Cfltaized, such as benzene. The reaction may be conducted lyzed Vapor Phase p The actual mechanics of the at atmospheric pressure or reduced pressure. Reduced invention are still unknown. However, two theories on pressure may be used to f ilit t vaporization f h the bond shifting that occurs are illustrated by the reactants and/or products. Reaction products comprise chemistry that follows:

a 2,2-disubstituted propiolactone having the formula lnall the above formulas R can be any straight or branched chain, saturated alkyl group containing 1-4 carbon atoms and R is a straight or branched chain saturated alkyl group containing 1-4 carbon atoms or a phenyl ,group.

The reaction is catalyzed by either an acidic or a basic type of catalyst. Virtually any acidic or basic catalyst will work so long as it is not removed in significant amounts in the product stream. Typical catalysts that are useful in this synthesis are silica-alumina, silica gel, one percent sodium carbonate on Celatom, five percent potassium hydroxide on Celatom, lanthanum oxide on silica gel, l2-tungstosilicic acid on silica gel,

ene bis(a-methyl hexanoate), methylene bis(methyl phenyl acetate), methylene bis(butyl phenyl acetate), and the like.

Reaction time will depend upon the catalyst and the temperature utilized but will normally be in the range of from about 0.1 second to about 30 seconds and preferably about 0.5 second to about seconds.

The process of the invention is illustrated in greater detail by the following examples, but it will be understood that these examples are not intended to limit the invention in any way and obvious modifications will occur to those skilled in the art. All examples are run at atmospheric pressure in a 2 foot by 22 mm. Vycor reactor.

EXAMPLE 1 This example demonstrates a method for the preparation of methylene diisobutyrate. To a two liter flask is added 7 moles of parafonnaldehyde, 7.35 moles of isobutyric anhydride,2.8 moles of isobutyric acid, and 2.0 grams of sulfuric acid. This mixture is reacted with stirring at 150C. for 16 hours. The reaction mixture is distilled on a l5-plate column with 1182 grams of methylene diisobutyrate being recovered at 96-l00C. at 20 mm. pressure. This represents a 90 percent yield and conversion based on paraformaldehyde.

EXAMPLE 2 This example illustrates the preparation of pivalolactone over an acidic catalyst.

Methylene diisobutyrate is fed to a pyrolysis tube which contains a silica-alumina catalyst and inert packing. The temperature of the catalyst bed and inert ma terial is maintained at 290: 20C, insuring that no liquid material will impinge on the catalyst surface. Nitrogen is used as a diluent and sweep gas. With a contact time of 5 seconds pivalolactone is produced in a 12 percent conversion.

EXAMPLE 3 This example illustrates the preparation of pivalolactone over a basic catalyst.

Methylene diisobutyrate is fed to a pyrolysis tube which contains a catalyst consisting of lanthanum oxide deposited on silica gel and inert packing. The temperature of the catalyst bed and inert material is maintained at 300i 15C, insuring that no liquid material will impinge on the catalyst surface Nitrogen is used as a diluent and sweep gas. With a contact time of 2 seconds pivalolactone is produced in a 5 percent conversion.

EXAMPLE 4 which comprises the steps of pyrolyzing a methylene diester having the formula wherein R is alkyl having l-4 carbon atoms and R is alkyl of from l-4 carbon atoms or phenyl at a temperature of from about 240C. to about 360C. in the presence of a catalyst selected from the group consisting of silica-alumina, silica gel, sodium carbonate on Celatom, potassium hydroxide on Celatom, lanthanum oxide on silica gel, l2-tungstosilicic acid on silica gel, and titania.

2. The process of claim 1 wherein the methylene di- I ester is selected from the group consisting of methylene diisobutyrate, methylene bis(dibutyl acetate), methylene bis(a-methyl hexanoate), methylene bis(methyl phenyl acetate), methylene bis(butyl'phenyl acetate). 3. The process of claim 1 wherein the catalyst is silica-alumina.

4. The process of claim 1 wherein'the catalyst is lanthanum oxide on silica gel.

5. The process of claim 1 wherein the pyrolysis is conducted at the temperature of fromabout 270C. to I about 310C.

6. The process of claim 1 wherein the pyrolysis is conducted at atmospheric pressure.

7. The process of claim 1 wherein the pyrolysis is conducted at reduced pressure.

8. A process for producing pivalolactone which consists essentially of the steps of pyrolizing methylene diisobutyrate at a temperature of from about 240C. to about 360C. in the presence ofa catalyst selected from the group consisting of silica-alumina, silica gel, sodium carbonate on Celatom, potassium hydroxide on Celatom, lanthanum oxide on silica gel, IZ-tungstosilicic acid on silica gel, and titania.

9. The process of claim 8 wherein the catalyst is silica-alumina.

10. The process of claim 8 wherein the catalyst consists of lanthanum oxide on silica gel.

ll. The process of claim 9 wherein the pyrolysis is conducted at a temperature of from about 270C. to about 310C.

12. The process of claim 9 wherein the pyrolysis is conducted at atmospheric pressure.

13. The process of claim 9 wherein the pyrolysis is conducted at reduced pressure.

14. A process for producing 2,2-disubstituted propiolactone having the formula whereby a methylene diester having the formula R 0 H o R wherein R is alkyl having l-4 carbon atoms and R is alkyl of from l-4 carbon atoms or phenyl, is pyrolyzed in the presence of a catalyst selected from the group consisting of silica-alumina, silica gel, one percent sodium carbonate on Celatom, five percent potassium hydroxide on Celatom, lanthanum oxide on silica gel. 12- tungstosilicic acid on silica gel, and titania, at a temperature of from about 240C. to about 360C.

15. The process of claim 14 wherein the methylene diester is selected from the group consisting of methylene diisobutyrate, methylene bis(dibutyl acetate), methylene bis(a-methyl hexanoate), methylene bis(- methyl phenyl acetate), methylene bis(butyl phenyl acetate).

16. The process of claim T4 wherein the pyrolysis is conducted at a temperature of from about 270C. to about 310C.

17. The process of claim 114 wherein the pyrolysis is conducted at atmospheric pressure.

18. The process of claim ll4 wherein the pyrolysis is conducted at reduced pressure.

19. A process for producing pivalolactone wherein methylene diisobutyrate is pyrolyzed in the presence of a catalyst selected from the group consisting of silicaalumina, silica gel, one percent sodium carbonate on Celatom, five percent potassium hydroxide on Celatorn, lanthanum oxide on silica gel, IZ-tungstosilicic acid on silica gel, and titania, at a temperature of from about 240C. to about 360C.

20. The process of claim 119 wherein the pyrolysis is conducted at a temperature of from about 270C. to about 310C.

21. The process of claim 1T9 wherein the pyrolysis is conducted at atmospheric pressure.

22. The process of claim 19 wherein the pyrolysis is conducted at reduced pressure. 

1. A PROCESS FOR PRODUCING 2,2-DISUBSTITUTED PROPIOLACTONE HAVING THE FORMULA
 2. The process of claim 1 wherein the methylene diester is selected from the group consisting of methylene diisobutyrate, methylene bis(dibutyl acetate), methylene bis( Alpha -methyl hexanoate), methylene bis(methyl phenyl acetate), methylene bis(butyl phenyl acetate).
 3. The process of claim 1 wherein the catalyst is silica-alumina.
 4. The process of claim 1 wherein the catalyst is lanthanum oxide on silica gel.
 5. The process of claim 1 wherein the pyrolysis is conducted at the temperature of from about 270*C. to about 310*C.
 6. The process of claim 1 wherein the pyrolysis is conducted at atmospheric pressure.
 7. The process of claim 1 wherein the pyrolysis is conducted at reduced pressure.
 8. A process for producing pivalolactone which consists essentially of the steps of pyrolizing methylene diisobutyrate at a temperature of from about 240*C. to about 360*C. in the presence of a catalyst selected from the group consisting of silica-alumina, silica gel, sodium carbonate on Celatom, potassium hydroxide on Celatom, lanthanum oxide on silica gel, 12-tungstosilicic acid on silica gel, and titania.
 9. The process of claim 8 wherein the catalyst is silica-alumina.
 10. The process of claim 8 wherein the catalyst consists of lanthanum oxide on silica gel.
 11. The process of claim 9 wherein the pyrolysis is conducted at a temperature of from about 270*C. to about 310*C.
 12. The process of claim 9 wherein the pyrolysis is conducted at atmospheric pressure.
 13. The process of claim 9 wherein the pyrolysis is conducted at reduced pressure.
 14. A process for producing 2,2-disubstituted Propiolactone having the formula
 15. The process of claim 14 wherein the methylene diester is selected from the group consisting of methylene diisobutyrate, methylene bis(dibutyl acetate), methylene bis( Alpha -methyl hexanoate), methylene bis(methyl phenyl acetate), methylene bis(butyl phenyl acetate).
 16. The process of claim 14 wherein the pyrolysis is conducted at a temperature of from about 270*C. to about 310*C.
 17. The process of claim 14 wherein the pyrolysis is conducted at atmospheric pressure.
 18. The process of claim 14 wherein the pyrolysis is conducted at reduced pressure.
 19. A process for producing pivalolactone wherein methylene diisobutyrate is pyrolyzed in the presence of a catalyst selected from the group consisting of silica-alumina, silica gel, one percent sodium carbonate on Celatom, five percent potassium hydroxide on Celatom, lanthanum oxide on silica gel, 12-tungstosilicic acid on silica gel, and titania, at a temperature of from about 240*C. to about 360*C.
 20. The process of claim 19 wherein the pyrolysis is conducted at a temperature of from about 270*C. to about 310*C.
 21. The process of claim 19 wherein the pyrolysis is conducted at atmospheric pressure.
 22. The process of claim 19 wherein the pyrolysis is conducted at reduced pressure. 